Deep white matter hyperintensities, microstructural integrity and dual task walking in older people

The clinical characteristics of cerebral small vessel disease patients with motoric cognitive risk syndrome during single- and dual-task walking

Objective

We aimed to (1) identify neuroimaging biomarkers of distinguishing motoric cognitive risk syndrome (MCRS) risk among older Chinese adults with cerebral small vessel disease (CSVD) and (2) detect differences in gait parameters and neuroimaging biomarkers between CSVD individual with and without MCRS, especially during dual-task walking (DTW).

Methods

We enrolled 126 inpatients with CSVD who were divided into two groups according to MCRS status. Data on basic parameters, variability, asymmetry, and coordination were collected during single-task walking (STW) and DTW. Neuroimaging features (white matter hyperintensities, lacunes, and microbleeds) and total disease burden were calculated. Analysis of variance and logistic regression analyses were applied to assess the role of STW, DTW, and neuroimaging biomarkers in MCRS.

Results

In total, 126 consecutive inpatients with CSVD were included (84 and 42 patients were classified as MCRS-negative and MCRS-positive, respectively). The MCRS-positive group showed poorer performance for nearly all gait parameters compared with the MCRS-negative group during cognitive DTW. Meanwhile, all gait parameters except asymmetry were assessed in participants with MCRS for significant deterioration during cognitive DTW compared with that during STW. However, only basic parameters differed between STW and cognitive DTW in participants without MCRS. A significant independent association between total CSVD scores and MCRS was also detected.

Conclusions

For CSVD patients, with higher total CSVD burden rather than any single neuroimaging marker, was linked to a greater risk of MCRS. In addition, CSVD individuals with MCRS had higher variability and phase coordination index (PCI), especially in cognitive DTW. Thus, they should concentrate more on their gait variability or coordination and reduce secondary task loads while walking in daily life, especially in cognitive secondary tasks.

The relationship between nutritional status and white matter integrity in older adults: A diffusion tensor imaging study

OBJECTIVES

The purpose of this study to determinate whether there is a relationship between the nutritional status and white matter integrity in older patients by using Diffusion Tensor Imaging (DTI).

METHODS

The patients were evaluated by Mini-Nutritional Assessment Scale. The patients are categorized in the groups of well-nourished, risk of malnutrition, or malnourished, depending on the overall score> 23.5, 17-23.5, or 17; respectively. All patients had brain MRI and DTI. The mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) values were calculated by ROI-based method in white matter tracts.

RESULTS

Total of the 224 patients; 86 patients had normal nutrition status (group 1), 107 patients were diagnosed with malnutrition risk (group 2) and 31 patients were diagnosed with malnutrition (group 3). Significantly decreased FA values of genu of corpus callosum, forceps minor and significantly increased MD values of middle cerebellar peduncle, and superior frontooccipital fasciculus were detected in group 2 in comparison to group 1 (p < 0.05). After adjusting for the folate and age, MD and RD values of cingulum remained significantly higher and the AD values of superior cerebellar peduncle remained significantly lower in group 3 (p < 0.05).

CONCLUSIONS

Malnutrition was associated with deteriorated DTI values, especially in cingulum and superior cerebellar peduncle. Assessing the nutritional status of older individuals is crucial to avoid its negative impact on brain.

ADVANCES IN KNOWLEDGE

Early diagnosis of malnutrition-related impaired WM integrity is important for prevention and intervention, and DTI is a useful non-invasive technique to be used for this purpose.

Variability, asymmetry, and bilateral coordination of gait during single- and dual-task walking of patients with cerebral small vessel disease

OBJECTIVE

We investigated coefficient of variation (CV), gait asymmetry (GA) and phase coordination index (PCI) in CSVD (cerebral small vessel disease) patients during STW (single task walking) and DTW (dual task walking) and explored the relationship between above parameters with disease severity and cognitive function.

METHODS

This cross-sectional study collected cognitive function indices and gait parameters from 23 healthy controls and 94 patients with CSVD during STW and DTW. According to the Fazekas scales, the severity of CSVD valued by white matter hyperintensity (WMH) were divided into control, mild, moderate, severe and control group. MRIs were analyzed for WMHs, CMB, lacunes, etc.

RESULTS

The control group showed lower PCI than CSVD patients during STW; no differences were detected among the disease severity groups. During DTW, all four groups exhibited significant differences in PCI and CV. For the moderate and severe groups, coordination and variation significantly differed between the two walking methods. There were correlations between the PCI and GA in the moderate and severe groups (R = 0.376, R = 0.573 during DTW; R = 0.414, R = 0.643 during STW), and no correlations in the control group and mild CSVD group. Conclusion: PCI and CV may be vital for detecting the symptoms in the early stage of CSVD disease. We also verified that the PCI could become the bridge across the cognition and motor disorder in CSVD, which was helpful for evaluating clinical symptoms comprehensively.

Altered brain spontaneous activity in patients with cerebral small vessel disease using the amplitude of low-frequency fluctuation of different frequency bands

Background

Previous studies showed that cerebral small vessel disease (cSVD) is a leading cause of cognitive decline in elderly people and the development of Alzheimer's disease. Although brain structural changes of cSVD have been documented well, it remains unclear about the properties of brain intrinsic spontaneous activity in patients with cSVD.

Methods

We collected resting-state fMRI (rs-fMRI) and T1-weighted 3D high-resolution brain structural images from 41 cSVD patients and 32 healthy controls (HC). By estimating the amplitude of low-frequency fluctuation (ALFF) under three different frequency bands (typical band: 0.01-0.1 Hz; slow-4: 0.027-0.073 Hz; and slow-5: 0.01-0.027 Hz) in the whole-brain, we analyzed band-specific ALFF differences between the cSVD patients and controls.

Results

The cSVD patients showed uniformly lower ALFF than the healthy controls in the typical and slow-4 bands (pFWE < 0.05). In the typical band, cSVD patients showed lower ALFF involving voxels of the fusiform, hippocampus, inferior occipital cortex, middle occipital cortex, insula, inferior frontal cortex, rolandic operculum, and cerebellum compared with the controls. In the slow-4 band, cSVD patients showed lower ALFF involving voxels of the cerebellum, hippocampus, occipital, and fusiform compared with the controls. However, there is no significant between-group difference of ALFF in the slow-5 band. Moreover, we found significant "group × frequency" interactions in the left precuneus.

Conclusion

Our results suggested that brain intrinsic spontaneous activity of cSVD patients was abnormal and showed a frequency-specific characteristic. The ALFF in the slow-4 band may be more sensitive to detecting a malfunction in cSVD patients.

Spatiotemporal gait characteristics during single- and dual-task walking are associated with the burden of cerebral small vessel disease

Introduction

Gait impairment is a common symptom among individuals with cerebral small vessel disease (CSVD). However, performance differences between single-task walking (STW) and dual-task walking (DTW) among individuals with CSVD remain unclear. Therefore, we aimed to examine differences in gait characteristics during STW and DTW as well as the association between gait performance and neuroimaging markers.

Methods

We enrolled 126 older individuals with CSVD. The speed, cadence, stride length, stride time, and their dual-task cost (DTC) or variability were measured under the STW, motor-cognitive DTW (cognitive DTW), and motor-motor DTW (motor DTW) conditions. We examined neuroimaging features such as white matter hyperintensities (WMHs), lacunes, microbleeds, and total burden. Further, we analysed the association of neuroimaging markers with gait performance, including gait variability and DTC.

Results

Almost all spatiotemporal characteristics, as well as their DTCs or variabilities, showed significant among-group differences according to disease severity in the cognitive DTW condition; however, relatively lesser differences were observed in the STW and motor DTW conditions. The total CSVD burden score was moderately correlated with all the spatial parameters, as well as their DTCs or variabilities, in the cognitive DTW condition. Moreover, WMHs showed a correlation with speed, stride time, and cadence, as well as their DTCs, in the cognitive DTW condition. Furthermore, lacunes showed a moderate correlation with speed, stride length, and the DTC of speed, whilst microbleeds were only related to the DTC of stride length in the cognitive DTW condition. Neuroimaging biomarkers were not correlated with spatiotemporal parameters in STW and motor DTW conditions after Bonferroni correction. Moreover, the correlation coefficient between the total CSVD burden score and gait parameters was greater than those of other biomarkers.

Discussion

Parameters in the cognitive DTW condition are more appropriate than those in the motor DTW condition for the evaluation of gait abnormalities in patients with CSVD. Moreover, the total CSVD burden score might have better predictive utility than any single neuroimaging marker. Patients with CSVD, especially those with moderate-to-severe disease, should concentrate more on their gait patterns and reduce the load of secondary cognitive tasks whilst walking in daily life.

Dual-task gait and white matter hyperintensities in Lewy body diseases: An exploratory analysis

Background

Parkinson’s disease (PD) and dementia with Lewy bodies (DLB) are part of a spectrum of Lewy body disorders, who exhibit a range of cognitive and gait impairments. Cognitive-motor interactions can be examined by performing a cognitive task while walking and quantified by a dual task cost (DTC). White matter hyperintensities (WMH) on magnetic resonance imaging have also been associated with both gait and cognition. Our goal was to examine the relationship between DTC and WMH in the Lewy body spectrum, hypothesizing DTC would be associated with increased WMH volume.

Methods

Seventy-eight participants with PD, PD with mild cognitive impairment (PD-MCI), PD with dementia or DLB (PDD/DLB), and 20 cognitively unimpaired participants were examined in a multi-site study. Gait was measured on an electronic walkway during usual gait, counting backward, animal fluency, and subtracting sevens. WMH were quantified from magnetic resonance imaging using an automated pipeline and visual rating. A median split based on DTC was performed. Models included age as well as measures of global cognition and cardiovascular risk.

Results

Compared to cognitively unimpaired participants, usual gait speed was lower and DTC was higher in PD-MCI and PDD/DLB. Low DTC participants had higher usual gait speed. WMH burden was greater in high counting DTC participants. Frontal WMH burden remained significant after adjusting for age, cardiovascular risk and global cognition.

Conclusion

Increased DTC was associated with higher frontal WMH burden in Lewy body disorders after adjusting for age, cardiovascular risk, and global cognition. Higher DTC was associated with age.

Localized White Matter Tract Integrity Measured by Diffusion Tensor Imaging Is Altered in People with Mild Cognitive Impairment and Associated with Dual-Task and Single-Task Gait Speed

BACKGROUND

Altered white matter (WM) tract integrity may contribute to mild cognitive impairment (MCI) and gait abnormalities.

OBJECTIVE

The purpose of this study was to determine whether diffusion tensor imaging (DTI) metrics were altered in specific portions of WM tracts in people with MCI and to determine whether gait speed variations were associated with the specific DTI metric changes.

METHODS

DTI was acquired in 44 people with MCI and 40 cognitively normal elderly controls (CNCs). Fractional anisotropy (FA) and radial diffusivity (RD) were measured along 18 major brain WM tracts using probabilistic tractography. The average FA and RD along the tracts were compared between the groups using MANCOVA and post-hoc tests. The tracts with FA or RD differences between the groups were examined using an along-tract exploratory analysis to identify locations that differed between the groups. Associations between FA and RD in whole tracts and in the segments of the tracts that differed between the groups and usual/dual-task gait velocities and gross cognition were examined.

RESULTS

Lower FA and higher RD was observed in right cingulum-cingulate gyrus endings (rh.ccg) of the MCI group compared to the CNC group. These changes were localized to the posterior portions of the rh.ccg and correlated with gait velocities.

CONCLUSION

Lower FA and higher RD in the posterior portion of the rh.ccg adjacent to the posterior cingulate suggests decreased microstructural integrity in the MCI group. The correlation of these metrics with gait velocities suggests an important role for this tract in maintaining normal cognitive-motor function.

The age-related contribution of cognitive function to dual-task gait in middle-aged adults in Spain: observations from a population-based study

BACKGROUND

Poor dual-task gait performance is associated with a risk of falls and cognitive decline in adults aged 65 years or older. When and why dual-task gait performance begins to deteriorate is unknown. This study aimed to characterise the relationships between age, dual-task gait, and cognitive function in middle age (ie, aged 40-64 years).

METHODS

We conducted a secondary analysis of data from community-dwelling adults aged 40-64 years that took part in the Barcelona Brain Health Initiative (BBHI) study, an ongoing longitudinal cohort study in Barcelona, Spain. Participants were eligible for inclusion if they were able to walk independently without assistance and had completed assessments of both gait and cognition at the time of analysis and ineligble if they could not understand the study protocol, had any clinically diagnosed neurological or psychiatric diseases, were cognitively impaired, or had lower-extremity pain, osteoarthritis, or rheumatoid arthritis that could cause abnormal gait. Stride time and stride time variability were measured under single-task (ie, walking only) and dual-task (ie, walking while performing serial subtractions) conditions. Dual-task cost (DTC; the percentage increase in the gait outcomes from single-task to dual-task conditions) to each gait outcome was calculated and used as the primary measure in analyses. Global cognitive function and composite scores of five cognitive domains were derived from neuropsychological testing. We used locally estimated scatterplot smoothing to characterise the relationship between age and dual-task gait, and structural equation modelling to establish whether cognitive function mediated the association between observed biological age and dual tasks.

FINDINGS

996 people were recruited to the BBHI study between May 5, 2018, and July 7, 2020, of which 640 participants completed gait and cognitive assessments during this time (mean 24 days [SD 34] between first and second visit) and were included in our analysis (342 men and 298 women). Non-linear associations were observed between age and dual-task performance. Starting at 54 years, the DTC to stride time (β=0·27 [95% CI 0·11 to 0·36]; p<0·0001) and stride time variability (0·24 [0·08 to 0·32]; p=0·0006) increased with advancing age. In individuals aged 54 years or older, decreased global cognitive function correlated with increased DTC to stride time (β=-0·27 [-0·38 to -0·11]; p=0·0006) and increased DTC to stride time variability (β=-0·19 [-0·28 to -0·08]; p=0·0002).

INTERPRETATION

Dual-task gait performance begins to deteriorate in the sixth decade of life and, after this point, interindividual variance in cognition explains a substantial portion of dual-task performance.

FUNDING

La Caixa Foundation, Institut Guttmann, and Fundació Abertis.

Gait variability predicts cognitive impairment in older adults with subclinical cerebral small vessel disease

Introduction

Advanced methods of gait research, including approaches to quantify variability, and orderliness/regularity/predictability, are increasingly used to identify patients at risk for the development of cognitive impairment. Cerebral small vessel disease (CSVD) is highly prevalent in older adults and is known to contribute to the development of vascular cognitive impairment and dementia (VCID). Studies in preclinical models demonstrate that subclinical alterations precede CSVD-related cognitive impairment in gait coordination. In humans, CSVD also associates with gait abnormalities. The present study was designed to test the hypothesis that increased gait variability and gait asymmetry predict a decline in cognitive performance in older adults with CSVD.

Methods

To test this hypothesis, we compared cognitive performance and gait function in patients with CSVD (age: 69.8 ± 5.3 years; n = 11) and age- and sex-matched control participants (age: 70.7 ± 5.8 years; n = 11). Based on imaging findings, patients with CSVD were identified [presence of white matter hyperintensities plus silent brain infarcts and/or microhemorrhages on magnetic resonance imaging (MRI) assessment]. Cognitive performance was assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Gait parameters were measured during the single and dual tasks, during which participants, in addition to the motor task, completed a series of mental arithmetic calculations. Spatial and temporal parameters of gait variability, symmetry, and permutation entropy were determined using a pressure-sensitive gait mat during single and dual cognitive task conditions.

Results

Patients with CSVD exhibited lower performance in a visual learning test (p = 0.030) and in a sustained attention test (p = 0.007). CSVD also affected step time variability (p = 0.009) and step length variability (p = 0.017). Step lengths of CSVD participants were more asymmetric (p = 0.043) than that of controls, while the two groups were statistically similar regarding step time symmetry and entropy of step time and length. Gait variability was inversely associated with sustained attention, especially among CSVD patients, and this relationship was significantly different between the two groups. The association of sustained attention with gait symmetry was also significantly different between the two groups.

Discussion

Our findings provide additional evidence in support of the concept that increased gait variability and asymmetry may predict cognitive impairment in older adults with CSVD.

Gait decline while dual-tasking is an early sign of white matter deterioration in middle-aged and older adults

Loss of white matter integrity (WMI) is associated with gait deficits in middle-aged and older adults. However, these deficits are often only apparent under cognitively demanding situations, such as walking and simultaneously performing a secondary cognitive task. Moreover, evidence suggests that declining executive functions (EF) are linked to gait decline, and their co-occurrence may point to a common underlying pathology, i.e., degeneration of shared brain regions. In this study, we applied diffusion tensor imaging (DTI) and a standardized gait assessment under single- and dual-tasking (DT) conditions (walking and subtracting) in 74 middle-aged and older adults without any significant gait or cognitive impairments to detect subtle WM alterations associated with gait decline under DT conditions. Additionally, the Trail Making Test (TMT) was used to assess EF, classify participants into three groups based on their performance, and examine a possible interaction between gait, EF, and WMI. Gait speed and subtracting speed while dual-tasking correlated significantly with the fractional anisotropy (FA) in the bilateral anterior corona radiata (highest r = 0.51/p &lt; 0.0125 FWE-corrected). Dual-task costs (DTC) of gait speed correlated significantly with FA in widespread pathways, including the corpus callosum, bilateral anterior and superior corona radiata, as well as the left superior longitudinal fasciculus (highest r = −0.47/p &lt; 0.0125 FWE-corrected). EF performance was associated with FA in the left anterior corona radiata (p &lt; 0.05); however, EF did not significantly mediate the effects of WMI on DTC of gait speed. There were no significant correlations between TMT and DTC of gait and subtracting speed, respectively. Our findings indicate that gait decline under DT conditions is associated with widespread WM deterioration even in middle-aged and older adults without any significant gait or cognitive impairments. However, this relationship was not mediated by EF.

Gait in Cerebral Amyloid Angiopathy

Background Gait is a complex task requiring coordinated efforts of multiple brain networks. To date, there is little evidence on whether gait is altered in cerebral amyloid angiopathy (CAA). We aimed to identify impairments in gait performance and associations between gait impairment and neuroimaging markers of CAA, cognition, and falls. Methods and Results Gait was assessed using the Zeno Walkway during preferred pace and dual task walks, and grouped into gait domains (Rhythm, Pace, Postural Control, and Variability). Participants underwent neuropsychological testing and neuroimaging. Falls and fear of falling were assessed through self-report questionnaires. Gait domain scores were standardized and analyzed using linear regression adjusting for age, sex, height, and other covariates. Participants were patients with CAA (n=29), Alzheimer disease with mild dementia (n=16), mild cognitive impairment (n=24), and normal elderly controls (n=47). CAA and Alzheimer disease had similarly impaired Rhythm, Pace, and Variability, and higher dual task cost than normal controls or mild cognitive impairment. Higher Pace score was associated with better global cognition, processing speed, and memory. Gait measures were not correlated with microbleed count or white matter hyperintensity volume. Number of falls was not associated with gait domain scores, but participants with low fear of falling had higher Pace (odds ratio [OR], 2.61 [95% CI, 1.59-4.29]) and lower Variability (OR, 1.64 [95% CI, 1.10-2.44]). Conclusions CAA is associated with slower walking, abnormal rhythm, and greater gait variability than in healthy controls. Future research is needed to identify the mechanisms underlying gait impairments in CAA, and whether they predict future falls.

Differential Relationships Between Brain Structure and Dual Task Walking in Young and Older Adults

Almost 25% of all older adults experience difficulty walking. Mobility difficulties for older adults are more pronounced when they perform a simultaneous cognitive task while walking (i.e., dual task walking). Although it is known that aging results in widespread brain atrophy, few studies have integrated across more than one neuroimaging modality to comprehensively examine the structural neural correlates that may underlie dual task walking in older age. We collected spatiotemporal gait data during single and dual task walking for 37 young (18–34 years) and 23 older adults (66–86 years). We also collected T₁-weighted and diffusion-weighted MRI scans to determine how brain structure differs in older age and relates to dual task walking. We addressed two aims: (1) to characterize age differences in brain structure across a range of metrics including volumetric, surface, and white matter microstructure; and (2) to test for age group differences in the relationship between brain structure and the dual task cost (DTcost) of gait speed and variability. Key findings included widespread brain atrophy for the older adults, with the most pronounced age differences in brain regions related to sensorimotor processing. We also found multiple associations between regional brain atrophy and greater DTcost of gait speed and variability for the older adults. The older adults showed a relationship of both thinner temporal cortex and shallower sulcal depth in the frontal, sensorimotor, and parietal cortices with greater DTcost of gait. Additionally, the older adults showed a relationship of ventricular volume and superior longitudinal fasciculus free-water corrected axial and radial diffusivity with greater DTcost of gait. These relationships were not present for the young adults. Stepwise multiple regression found sulcal depth in the left precentral gyrus, axial diffusivity in the superior longitudinal fasciculus, and sex to best predict DTcost of gait speed, and cortical thickness in the superior temporal gyrus to best predict DTcost of gait variability for older adults. These results contribute to scientific understanding of how individual variations in brain structure are associated with mobility function in aging. This has implications for uncovering mechanisms of brain aging and for identifying target regions for mobility interventions for aging populations.

Gait characteristics under single-/dual-task walking conditions in elderly patients with cerebral small vessel disease: Analysis of gait variability, gait asymmetry and bilateral coordination of gait

BACKGROUND

Dual-task walking (DTW) is common in daily life and represents an ideal paradigm for elucidating gait irregularity. Under single-task walking (STW) and DTW conditions, the symmetric and bilaterally coordinated human gait pattern found in healthy individuals is absent in individuals with neurological ailments such as Parkinson's disease, Alzheimer's disease and post-stroke issues. Cerebral small vessel disease (CSVD) is a neuropathological and radiological issue that has been reported to be associated with cognitive and motor disorders. However, few gait analyses have focused on elderly individuals with CSVD under DTW conditions.

RESEARCH QUESTION

Are parameters of gait analysis helpful in elucidating gait abnormalities in elderly patients with CSVD under DTW conditions?

METHODS

A total of 46 elderly patients with CSVD (CSVD group) and 22 healthy, age-matched individuals (HE group) were recruited. Gait data were collected from both groups under STW and DTW conditions. Direct parameters and metrics reflecting gait variability, gait asymmetry, and bilateral coordination of gait in the two groups were compared.

RESULTS

Under STW conditions, elderly individuals with CSVD showed markedly shorter stride length, were slower, and had higher gait asymmetry (GA) and phase coordination index (PCI) than healthy controls after adjusting for age, sex and level of education. Under DTW conditions, there were statistically significant differences between the two groups in stride time, stride length, cadence, stride time variability, GA and PCI after adjusting for age, sex, and level of education.

SIGNIFICANCE

Reanalysis-generated parameters, such as gait variability, GA, and PCI, are biomarkers for gait dysfunction in elderly patients with CSVD. In this study, elderly individuals with CVSD showed abnormal gait features under both STW and DTW conditions.

Cerebral Microbleeds Were Related With Poor Cognitive Performances on the Dual Task Condition in Older Adults

Background: The dual task (DT) was commonly used to assess the risk of falls in older adults and patients with neurological disorders. However, the performance on DT conditions has not been well investigated in patients with cerebral microbleed (CMB). This study is aimed to compare the performance in DT tests between older adults with and without CMB, and to explore the association between CMB and cognitive performances of DT.

Methods: This is a cross-sectional study. A total of 211 old adults participated, involving 68 CMB patients. The task protocol involved two global cognition tests, two single cognitive tests (serial 7 subtraction and semantic fluency), two single motor tasks [8-m walking and timed up and go test (TUG)], and three DT tests [walking and serial subtraction (WSS), walking and semantic fluency (WSF), and TUG and serial subtraction (TUGSS)]. The time taken to complete each task and the number of correct responses were recorded. For each DT condition, the correct response rate (CRR) and the dual-task effect (DTE) for the correct number were calculated.

Results: Compared with subjects without CMB, CMB patients had worse cognitive performances on DT condition in CRR of WSS (p = 0.003), WSF (p = 0.030) and TUGSS (p = 0.006), and DTE of WSS (p = 0.017). Binary logistic regression analysis showed that the presence of CMB was an independent risk factor for the impairment group for CRR of TUGSS (OR, 2.54; 95% CI, 1.11–5.82; p = 0.027) with the adjustment for confounders, rather than CRR of WSS and WSF, or DTE of WSS. Multiple linear regression analysis showed that CRR of TUGSS decreased with the increase of CMB number grades (β, −0.144; 95% CI, −0.027, −0.002; p = 0.028).

Conclusion: The present study indicated that CMBs were closely associated with poor cognitive performances on DT in the elderly. Strongest effect size was seen for CRR of TUGSS, where performance deficits increased in proportion to the degree of CMB burden.

The Effects of Tau, Amyloid, and White Matter Lesions on Mobility, Dual Tasking, and Balance in Older People

Background

This study aimed to investigate whether white matter lesions (WML), β-amyloid-, and tau pathologies are independently associated with mobility, dual tasking, and dynamic balance performance in older nondemented individuals.

Methods

We included 299 older people (mean, SD, age: 71.8, 5.6 years) from the Swedish BioFINDER study, whereof 175 were cognitively unimpaired and 124 had mild cognitive impairment (MCI). In multivariable regression analyses, dependent variables included mobility (Timed Up & Go [TUG]), dual tasking (TUG with a simultaneous subtraction task, that is, TUG-Cog, as well as dual task cost), and balance (Figure-of-eight). The analyses were controlled for age, sex, education, diagnosis (ie, MCI), and comorbidity (stroke, diabetes, and ischemic heart disease). Independent variables included WML volume, and measures of β-amyloid (abnormal cerebrospinal fluid [CSF] Aβ42/40 ratio) and tau pathology (CSF phosphorylated tau [p-tau]).

Results

Multivariable regression analyses showed that an increased WML volume was independently associated with decreased mobility, that is, TUG (standardized β = 0.247; p < .001). Tau pathology was independently associated with dual tasking both when using the raw data of TUG-Cog (β = 0.224; p = .003) and the dual-task cost (β= −0.246; p = .001). Amyloid pathology was associated with decreased balance, that is, Figure-of-eight (β = 0.172; p = .028). The independent effects of WML and tau pathology were mainly observed in those with MCI, which was not the case for the effects of amyloid pathology on balance.

Conclusions

Common brain pathologies have different effects where WML are independently associated with mobility, tau pathology has the strongest effect on dual tasking, and amyloid pathology seems to be independently associated with balance. Although these novel findings need to be confirmed in longitudinal studies, they suggest that different brain pathologies have different effects on mobility, balance, and dual-tasking in older nondemented individuals.

Changes in Metabolic Activity and Gait Function by Dual-Task Cognitive Game-Based Treadmill System in Parkinson's Disease: Protocol of a Randomized Controlled Trial

Balance and gait impairments, and consequently, mobility restrictions and falls are common in Parkinson’s disease (PD). Various cognitive deficits are also common in PD and are associated with increased fall risk. These mobility and cognitive deficits are limiting factors in a person’s health, ability to perform activities of daily living, and overall quality of life. Community ambulation involves many dual-task (DT) conditions that require processing of several cognitive tasks while managing or reacting to sudden or unexpected balance challenges. DT training programs that can simultaneously target balance, gait, visuomotor, and cognitive functions are important to consider in rehabilitation and promotion of healthy active lives. In the proposed multi-center, randomized controlled trial (RCT), novel behavioral positron emission tomography (PET) brain imaging methods are used to evaluate the molecular basis and neural underpinnings of: (a) the decline of mobility function in PD, specifically, balance, gait, visuomotor, and cognitive function, and (b) the effects of an engaging, game-based DT treadmill walking program on mobility and cognitive functions. Both the interactive cognitive game tasks and treadmill walking require continuous visual attention, and share spatial processing functions, notably to minimize any balance disturbance or gait deviation/stumble. The ability to “walk and talk” normally includes activation of specific regions of the prefrontal cortex (PFC) and the basal ganglia (site of degeneration in PD). The PET imaging analysis and comparison with healthy age-matched controls will allow us to identify areas of abnormal, reduced activity levels, as well as areas of excessive activity (increased attentional resources) during DT-walking. We will then be able to identify areas of brain plasticity associated with improvements in mobility functions (balance, gait, and cognition) after intervention. We expect the gait-cognitive training effect to involve re-organization of PFC activity among other, yet to be identified brain regions. The DT mobility-training platform and behavioral PET brain imaging methods are directly applicable to other diseases that affect gait and cognition, e.g., cognitive vascular impairment, Alzheimer’s disease, as well as in aging.

The association between white matter hyperintensity volume and gait performance under single and dual task conditions in older people with dementia: A cross-sectional study

BACKGROUND

Understanding the relationship between white matter hyperintensities (WMHs) and gait may assist in understanding the central control of gait and determining treatment modalities. These relationships are yet to be realized in older people with dementia.

OBJECTIVE

To examine the association between WMH volume and gait under single-task and dual task (DT) conditions in people with dementia.

METHODS

Twenty-eight community-dwelling older people with dementia (median age=83 years; [IQR=77-86]; 36% female) had timed gait speed assessed at usual pace. Gait (speed, stride length, cadence) was assessed using the GAITRite® mat under three conditions (n = 18/28): a) single-task, b) functional DT: carrying a glass of water and c) cognitive DT: counting backwards from 30. WMH volumes were quantified using a fully automated segmentation toolbox.

RESULTS

Total, temporal and parietal WMH volumes were negatively correlated with timed and functional DT gait speed, and with stride length under single-task, functional DT and cognitive DT conditions. Frontal WMH volumes were negatively correlated with timed gait speed and stride length under single-task and functional DT conditions. Participants with higher total WMH burden had significantly slower timed and functional DT gait speed and reduced stride length under single-task, functional DT and cognitive DT conditions compared to participants with lower WMH burden.

CONCLUSIONS

WMH volume was associated with slower gait speed and reduced stride length, but not cadence, under single-task and DT conditions in people with dementia. Further research is needed to confirm these findings and determine whether vascular risk management can improve gait in older people with dementia.

Longitudinal Associations Between Gait, Falls, and Disability in Community-Dwelling Older Adults With Type II Diabetes Mellitus: Findings From The Irish Longitudinal Study on Ageing (TILDA)

BACKGROUND

Diabetes is associated with gait deficits, future falls, and disability; however, it is unclear if associations remain after controlling for relevant confounders. This study investigated (i) the effects of type II diabetes on spatiotemporal gait parameters in community-dwelling older adults and (ii) if diabetes status was independently associated with future falls and disability, after controlling for gait and other confounders.

METHOD

Baseline data were obtained from 2608 community-dwelling adults (≥60 years) participating in The Irish Longitudinal Study on Ageing (TILDA). Diabetes was identified from self-reported doctors' diagnosis, medications, and glycated hemoglobin levels. Gait characteristics were obtained during single- and dual-task walking using a GAITRite mat (n = 2560). Incident falls and disability were collected over 4 years follow-up (n = 2473). Associations between diabetes status and gait (cross-sectional) and falls and disability (longitudinal) were investigated using regression analysis, adjusting for medications, cardiovascular health, neuropsychological function, and fall-related factors.

RESULTS

Diabetes (prevalence = 9.1%) was cross-sectionally associated with shorter dual-task step length after adjusting for covariates (β = -1.59, 95% CI: -3.10, -0.08, p < .05). Diabetes was independently associated with increased risk of future instrumental activity of daily living (IADL) difficulty in those with no prior difficulty (incidence rate ratio [IRR] = 1.51, 95% CI: 1.08, 2.11, p < .05) although dual-task step length was an important confounder in all disability models. No independent associations between diabetes and falls were observed.

CONCLUSIONS

Diabetes was independently associated with shorter dual-task step length and increased risk of future IADL difficulty. Multidimensional interventions addressing poor health and function in those with diabetes may help reduce the risk of gait deficits and future disability.

Association of Static Posturography With Severity of White Matter Hyperintensities

Background: Impaired gait and balance are associated with severity of leukoaraiosis. Evaluation of balance is based on neurological examination using Romberg's test with bipedal standing, assessment scale, and posturographic parameters. The goal of this study was to determine the relationship between static equilibrium and grades of white matter hyperintensities (WMHs) using static posturography as a quantitative technical method.

Method: One hundred and eighteen (118) patients with lacunar infarct were recruited and assessed on MRI with Fazekas's grading scale into four groups. On admission, age, gender, height, weight, Berg Balance Scale (BBS), mini-mental state examination (MMSE), and static posturography parameters were recorded, and their correlations with WMHs were determined.

Results: Age was significantly and positively correlated with severity of WMHs (r = 0.39, p < 0.05). WMH score was negatively correlated with BBS score (r = −0.65, p < 0.05) and MMSE score (r = −0.79, p < 0.05). There was a significant positive correlation between track length anteroposterior (AP, with eyes closed) and severity of WMHs (r = 0.70, p < 0.05). Partial correlation analysis and multiple logistic regression analysis indicated that track length AP with eyes closed, was a predictor for the severity of WMHs (p< 0.05).

Conclusion: The severity of WHMs is associated with age, cognitive decline, and impairment in balance. Posturography parameter in track length in AP direction with eyes closed in relation to cognition and balance, may be a potential marker for disease progression in WMHs.

Heart Rate Variability Mainly Relates to Cognitive Executive Functions and Improves Through Exergame Training in Older Adults: A Secondary Analysis of a 6-Month Randomized Controlled Trial

Heart rate variability (HRV) mirrors autonomic nervous system activities and might serve as a parameter to monitor health status in older adults. However, it is currently unknown which functional health measures, including cognitive, physical, and gait performance parameters, are most strongly related to HRV indices. This knowledge would enable implementing HRV assessments into health monitoring routines and training planning for older adults. Simultaneous cognitive-motor and exergame training may be effective to improve HRV indices but has not been investigated yet. Eighty-nine healthy older adults (≥70 years of age) were randomized into three groups: (1) virtual reality video game dancing, i.e., exergaming (DANCE); (2) treadmill walking with simultaneous verbal memory training (MEMORY); or (3) treadmill walking only (PHYS). Strength and balance exercises complemented each program. Over 6 months, two weekly 1-h training sessions were performed. HRV indices (standard deviation of N-N intervals, SDNN; root mean square of successive R-R interval differences, RMSSD; and absolute power of high-frequency band (0.15-0.4 Hz), HF power) and various measures of cognitive, physical, and gait performance were assessed at baseline and after 3 months and 6 months. Multiple linear regression analyses with planned comparisons were calculated. At baseline, 8-12% of HRV variance was significantly explained by cognitive executive functions and leg strength (inversely related). Verbal long-term memory, aerobic and functional fitness, and gait performance did not contribute to the model (SDNN: R² = 0.082, p = 0.016; RMSSD: R² = 0.121, p = 0.013; HF power: R² = 0.119, p = 0.015). After 6 months, DANCE improved HRV indices, while MEMORY and PHYS did not (time × intervention interactions: first-contrast DANCE/MEMORY vs. PHYS: SDNN p = 0.014 one-tailed, ΔR ² = 0.020 and RMSSD p = 0.052 one-tailed (trend), ΔR ² = 0.007; second-contrast DANCE vs. MEMORY: SDNN p = 0.002 one-tailed, ΔR ² = 0.035, RMSSD p = 0.017 one-tailed, ΔR ² = 0.012, and HF power p = 0.011 one-tailed, ΔR ² = 0.013). We conclude that mainly cognitive executive functions are associated with HRV indices and that exergame training improves global and parasympathetic autonomic nervous system activities in older adults. Periodic assessments of HRV in older citizens could be particularly beneficial to monitor cognitive health and provide indications for preventative exercise measures.

[White matter hyperintensities in ageing: Pathophysiology, associated cognitive disorders and prevention]

White matter hyperintensities (WMH), also known as leukoaraïosis are very common neuroradiological manifestations in the elderly. The main risk factors for WMH are age and high blood pressure. The vascular origin of these lesions is classically accepted and WMH are considered as one feature of the small vessel disease. WMH may be associated with clinical symptoms, depending notably on their importance according to age. They are associated with increased mortality, strokes and changes in cognition with a higher risk of dementia (vascular dementia or Alzheimer's disease). Modification of vascular risk factors could have a beneficial effect, but few evidences from controlled trials are available.

Understanding the association between psychomotor processing speed and white matter hyperintensity: A comprehensive multi-modality MR imaging study

Cognitive processing speed is crucial for human cognition and declines with aging. White matter hyperintensity (WMH), a common sign of WM vascular damage in the elderly, is closely related to slower psychomotor processing speed. In this study, we investigated the association between WMH and psychomotor speed changes through a comprehensive assessment of brain structural and functional features. Multi-modal MRIs were acquired from 60 elderly adults. Psychomotor processing speeds were assessed using the Trail Making Test Part A (TMT-A). Linear regression analyses were performed to assess the associations between TMT-A and brain features, including WMH volumes in five cerebral regions, diffusivity parameters in the major WM tracts, regional gray matter volume, and brain activities across the whole brain. Hierarchical regression analysis was used to demonstrate the contribution of each index to slower psychomotor processing speed. Linear regression analysis demonstrated that WMH volume in the occipital lobe and fractional anisotropy of the forceps major, an occipital association tract, were associated with TMT-A. Besides, resting-state brain activities in the visual cortex connected to the forceps major were associated with TMT-A. Hierarchical regression showed fractional anisotropy of the forceps major and regional brain activities were significant predictors of TMT-A. The occurrence of WMH, combined with the disruption of passing-through fiber integrity and altered functional activities in areas connected by this fiber, are associated with a decline of psychomotor processing speed. While the causal relationship of this WMH-Tract-Function-Behavior link requires further investigation, this study enhances our understanding of these complex mechanisms.

Minor gait impairment despite white matter damage in pure small vessel disease

OBJECTIVE

Gait impairment is common in patients with cerebral small vessel disease (SVD). However, gait studies in elderly SVD patients might be confounded by age-related comorbidities, such as polyneuropathy or sarcopenia. We therefore studied young patients with the genetically defined SVD CADASIL. Our aim was to examine the effects of pure SVD on single and dual task gait, and to investigate associations of gait performance with cognitive deficits and white matter alterations.

METHODS

We investigated single task walking and calculatory, semantic, or motoric dual task costs in 39 CADASIL patients (mean age 50 ± 8) using a computerized walkway. We obtained 3.0T MRI and neuropsychological data on processing speed, the main cognitive deficit in CADASIL. Spatiotemporal gait parameters were standardized based on data from 192 healthy controls. Associations between white matter integrity, assessed by diffusion tensor imaging, and gait were analyzed using both a global marker and voxel-wise analysis.

RESULTS

Compared to controls, CADASIL patients showed only mild single task gait impairment, and only in the rhythm domain. The semantic dual task additionally uncovered mild deficits in the pace domain. Processing speed was not associated with gait. White matter alterations were related to single task stride length but not to dual task performance.

INTERPRETATION

Despite severe disease burden, gait performance in patients with pure small vessel disease was relatively preserved in single and dual tasks. Results suggest that age-related pathologies other than small vessel disease might play a role for gait impairment in elderly SVD patients.

Associations between handgrip strength and mild cognitive impairment in middle-aged and older adults in six low- and middle-income countries

OBJECTIVES

A number of small-scale, single-country studies have suggested that muscular weakness may be a biomarker for cognitive health, mild cognitive impairment (MCI), and dementia. However, multinational, representative studies are lacking, particularly from low- and middle-income countries (LMICs). Thus, we assessed the association between muscular strength (measured by maximal handgrip) and MCI in six LMICs (China, Ghana, India, Mexico, Russia, and South Africa), using nationally representative data.

METHODS

Cross-sectional, community-based data on individuals aged 50 years or older from the World Health Organization's Study on Global Ageing and Adult Health were analyzed. MCI was defined according to the National Institute on Aging-Alzheimer's Association criteria. Weak handgrip strength was defined as less than 30 kg for men and less than 20 kg for women using the average value of two handgrip measurements of the dominant hand. Multivariable logistic regression analysis was conducted to assess the association between muscular strength and MCI.

RESULTS

A total of 32 715 participants were included (mean age 62 ± SD 15.6 y and 51.7% female). The prevalence of MCI and weak handgrip strength was 15.3% (95% CI, 14.4%-16.3%) and 46.5% (95% CI, 43.6%-49.5%), respectively. After adjustment for potential confounders, weak handgrip strength was associated with 1.41 (95% CI, 1.23-1.61) times higher odds for MCI. The corresponding figures for those aged 50 to 64 years and 65 years or older were 1.35 (95% CI, 1.14-1.60) and 1.54 (95% CI, 1.27-1.86), respectively.

CONCLUSIONS

Muscular weakness may provide a clinically useful indicator of MCI risk. Increasing our understanding of the connection between muscular and cognitive function could ultimately lead to the development and broader implementation of resistance training interventions targeting both physical and cognitive health.

The SNP43 (G/A) polymorphism in CAPN10 gene confers an increased risk of cognitive impairment in cerebral small vessel disease

BACKGROUND

Cognitive impairment, significantly reducing processing speed and executive function, is the critical consequence of cerebral small vessel disease (SVD), in which genetic variations have been studied. In this study, we explore the role of SNP43 (G/A) and SNP63 (C/T) polymorphism in the CAPN10 on cognitive impairment process in cerebral SVD.

METHODS

Cerebral SVD patients (n = 224) and healthy controls (n = 187) were recruited. The relationship between frequency distribution of SNP43 (G/A) and SNP63 (T/C) genotype and allele in CAPN10 gene, and cognitive impairment was examined. The independent risk factors for cognitive impairment in SVD were determined by logistic regression analysis.

RESULTS

Accordingly, the frequency distribution of genotype and allele at SNP43 (G/A) was significantly different between cerebral SVD patients and healthy controls. Cerebral SVD patients with GG genotype were more susceptible for cognitive impairment, whereas cerebral SVD patients with GA + AA genotype were less possible to suffer from cognitive impairment, compared with those with GG genotype. And also, cerebral SVD does not include SNP63 (C/T) to associate with cognitive impairment, and SNP43 (G/A), total cholesterol, triglyceride, low-density lipoprotein, and high-density lipoprotein were independent risk factors for cognitive impairment in SVD.

CONCLUSION

Our study provides evidence that SNP43 (G/A) in the CAPN10 gene increases the risk of cognitive impairment in SVD patients. Besides it is proven that, patients with G allele are more susceptible to suffer from cerebral SVD with worse cognitive impairment.